In all franchises which may be granted by any state, parish, or municipal corporation, the parish of Orleans excepted, for any street or interurban railway, there shall be a provision that all children, attending the schools in the city or parish in which the railway is situated, shall be afforded transportation over such railway at a price not exceeding three-fifths of the regular fare.  Each child shall have the right to the reduced fare only when going to or returning from school, and only when in possession of a certificate from the principal of the school which the child attends, declaring that the child is a pupil of the school.